Brush for dynamo-electric machines



June 2, 1931.

w. H. HARDMAN 1,808,549

BRUSH FOR DYNAMO ELECTRIC MACHINES Filed Oct. 15, 1927 Inventor: William H.Har"dr-nan,

' His Atno'rney.

Patented June 2, 1931 i UNITED STATES PATENT OFFICE WILLIAM H. HARDIAN, OI SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK BRUSH FOR DYNAIO-ELICTRIO MACHINES Application filed October 15, 1927. Serial No. 226,413.

- My invention relates to brushes for dynamo-electric machines.

Brushes as heretofore made have been provided with a flexible connector rigidly 6 attached .to the brush by rivets or screws for connecting the brush to the brush holder. These brushes have been subjected to vibration or repeated heating and cooling during the operation of the machines in which they were used so that the screws or rivets securing the flexible connectors to the brushes have been loosened which impaired the electrical connection between the connectors and the brushes and caused destructive arcing between them.

The object of my invention is to prov de an improved fastening means for securing the flexible connector to the brush so that it will not be loosened by vibration or re 2!) peated heating and cooling and so that destructive arcing between the brush and connector will be avoided. I do this by securing the flexible connector to the brush by means including a spring arranged to yieldably urge the connector against the brush. My invention will be more fully set forth in the followin description referring to the accompanying rawings and the features of novelty which characterize my invention will be pointed out with particularity 1n the claims annexed to and forming a part of this specification.

In the drawings, Fi 1 is a perspectlve view of a brush embo ying my invention; Fig. 2 is a transverse section on the line 2-2 of Fig. 1, and Fig. 3 is a view of the hollow rivet employed showing the relation of the parts for securing the flexible connector to the brush.

Referring to the drawings, the brush 10 illustrated is formed with an opening 11 therethrough and recesses 12 and 13 around the openingon opposite sides thereof, the recess 12 extending to the top of the brush so that the flexible connector 14 will not prevent the brush passing into the brush holder.

In accordance with my invention the connector is secured to the brush by means including a spring member retained under ,portion 14a of the compression which will maintain a ood electrical connection with the brush i the securing means should become loosened. In the construction illustrated by way of example, the connector is provided with a terminal portion 14a which is secured in the recess 12 by a rivet 15 or any other suitable securing means extending throu h the terminal portion and the brush. 11 order to prevent the terminal portion of the connector being loosened by vibration or heating and cooling of'the brush and resultant destructive arcing between the connector and the brush, I arrange a spring member "such as a spring washer 16 on the rivet 15 and in the recess 13 between two flat washers 17 and upset the rivet at each end to compress the spring washer 16 and .retain the terminal portion of the connector against the brush under the action of the spring washer. By the arrangement if the rlvet should be loose'ned by vibration or heating and cooling of the brush the spring washer 16 will firmly retain the terminal connector against the brush and maintains a good electrical connection therewith.

Although I have shown my invention applied to a carbon brush having a rivet for securing the flexible connector to the brush other securing means may be used. I do not, therefore, limltd except claims.

What I claim as new anddesire to secure by Letters Patent of the United States is defined in the appended 1. In combination a brush having an opening therein, a flexible conductor, and means extending through said openin for securing said conductor to said brus including a tubularv rivet and a spring on said rivet.

2. In combination, a brush having an opening therein and a recess at each end 0 the opening, a flexible conductor having a terminal portion arranged in one recess and a spring member arranged in the other recess, and means extending through said opening engaging said spring member and desire my invention to be said terminal portion for yieldingly retaining the latter in said recess.

3. In combination, a brush having an opening therein and a recess at each end of 5 the opening, a flexible conductor having a terminal portion arranged in one recess and a spring member comprising two washers having a spring Washer therebetween arranged in the other recess, and means engaging said terminal portion and extending through said spring member to compress the spring and yieldably retain the terminal portion in said recess.

4. In combination, a brush having an opening therein and a recess at each end of the opening, a flexible conductor having a terminal portion arranged in one recess and a spring member arranged in the other recess, and a tubular rivet extending through go said opening, said rivet being upset at both ends to retain said spring member under compression and said terminal portion in its recess under the action of said spring member. In Witness whereof, I have hereunto set my hand this 14th day of October, 1927.

WILLIAM H. HARDMAN. 

